Ive been around rentals for a long time (rental trucks, standard RENT-ALL type items and bike, canoe, kayak rentals) and in every case either you offer the renter some kind of insurance or you as the business owner takes out insurance. It is most definatly not common practice to charge full retail to a customer for fixing a rental item when they dont have the option to take out insurance on the item to begin with. Its not like your renting out beach cruisers to cruise the boardwalk, these bikes are going to be jumped, dropped, wrecked, slammed into rocks and covered in west virginia mountain poo.... the MAC needs to insure these things.